Correct: `Array.from()` (it’s a static method) Incorrect: `Array.join()` (doesn’t exist; it’s a prototype method) This patch uses the common `#` syntax to denote `.prototype.`.
487 B
487 B
percentile
Uses the percentile formula to calculate how many numbers in the given array are less or equal to the given value.
Use Array.prototype.reduce() to calculate how many numbers are below the value and how many are the same value and apply the percentile formula.
const percentile = (arr, val) =>
(100 * arr.reduce((acc, v) => acc + (v < val ? 1 : 0) + (v === val ? 0.5 : 0), 0)) / arr.length;
percentile([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 6); // 55